Method of making cyanids.



No. 682,74I. Patented Sept. I7, |90I. J. PFLEGER.

METHOD 0F MAKING GYANIDS.

(Application med nec. 1o, 1900.)

(N o M od el mim@ 21.5% y v {JI/komma@ rn: unam: versus ca, Puomwmmmaniac-.Tom r. c.

UNITED STATES PATENT OFFICE.

JOHANNES PELEGER, OE EEANKFORT-oN-THE-MAIN, GERMANY, AssIGNoR ToDEUTSCHE GOLD a sILBEE-soHEIDE-ANSTALT, VORM. RoEssLER, OE

SAME PLACE.

METHOD OF MAKING'CY'ANIDS'.

SPECIFICATION forming part of Letters Patent No. 682,741, datedSeptember 17, 1901.- Applieation filed December 10, 1900. Serial N o.39.382. (No specimens.)

T all whom it may concern:

Be it known that I, JOHANNES PFLEGER, a subject of the Emperor ofGermany, and a resident of 215 Gutleutstrasse, Frankfort-onthe-Main,Germany, have invented certain new and useful Improvements in theManufacture of Cyanids, of which the following is a specification.

In the United States Patent No. 543,643 it 1o is stated that thesynthesis of the cyanids from an alkali metal, ammonia, and carbon inone operation gives insuficient results,and the reason given-for this isthat the high ternperature which is necessary t0 maintain for theformation of the cyanid is detrimental to the unchecked formation of thealkali amids. To render possible an unchecked synthesis of the cyanidswith the aforesaid substances and to obtain a good yield, it is neezoessary according to the aforesaid specification to divide the processinto two operationsY and to carry it out in two apparatuses. I havediscovered that this is not necessary and that the synthesis by means ofsodium, ammonia, and carbon can be carried out' in a single apparatusand in one operation, if the conditions stated in the specification ofmy application, Serial No. 39,383, of even date herewith, for LettersPatent, for. the preparation of cyanamid and its compounds are observed.In the said specication is described a new process for preparation ofdialkalicyanamide-such as, for instance, the disodiumcyanamid, (N a2NONDrechsel, (see the 3 5 JournaZf/Lr Praktische Chem/ie, (2,) 2l, p. 90,)

has found that dialkalicyanamid compounds can be converted into alkalicyanids by fusing them with carbon. For the synthetical production ofcyanids according to this inven- 40 tion cyanamid is prepared, but inpresence of as much carbon as will cause all the alkali cyanamid to beconverted into cyanid.

The accompanying drawing shows a melting vessel in sectional elevation,in which my process may be carried out.

In the drawing, a is the vessel, b the charging-opening through whichthe gases escape, while c is the tube through which the ammonia is letin.

This invention may be carried out as follows: In the melting vessel a,which may be built in a furnace capable of efficient regulation, thecyanid-for instance, sodium cyanid--is melted, and then the calculatedquantity of alkali metal and carbon is added thereto. At a temperaturethat is just sufcient to keep the cyanid in a liuid state a current ofammonia of suitable strength is caused to pass through the mixture.About one hundred and fifty kilograms of potassium 6o cyanid are melted.Then aboutseventy kilograms of charcoal and about one hundred kilogramsof metallic sodium are added. Then ammonia is let in until all themetallic sodium has disappeared. The temperature of the molten ymassshould first be about 550 centigrade. Durin'g the processthe`temperature is successively raised until it is at the end of theoperation about 8000 centigrade. The duration of the process is from tento 7o twelve hours; Vbut I do not confine my invention to these exactlimits, as they may vary somewhat. The following reactions then takeplace: First, the metal and the ammonia unite to form an alkali amid,which in its nascent state combines at once with the cyanid to form adialkalicyanamid, with which latter the carbon combines, so that acyanid is formed. In order that the last-named reaction, the addition ofcarbon to the dialkalicy- 8o anamid, may take place quantitatively, thetemperature of the reacting mixture must be raised a little toward theend of the Operation.

The above-described reactions may be expressed by the followingequations:

By combining Equations I and II the reac- 9o tions may be expressed asfollows:

in two equations.

The great advantage of this process resides, first of all, in the factthat the amid, which is easily decomposed at a high temperature, is,owing toits being at the moment of its Ioo formation absorbed by thepreviously-introduced cyanid and transformed into the much more stableoyanamid, protected by this very process against decomposition, and inconsequence can be quantitatively converted into cyanid at the hightemperature. Besides this advantage, the apparatus is of the simplestkind that can be imagined, and the Whole process of formation of thecyanid by means of sodium, ammonia, and carbon is carried out in onesingle Crucible, which Was not possible when operating in accordancewith the specification of the aforesaid patent. In lieu of sodium andsodium cyanid any other a1- kali metal and its cyanid may of course beused.

I claim- The herein-described process for the produc tion of alkalioyands, Which consists in reacting ammonia With a mixture of alakalimetal, carbon and cyanid, at a temperature not substantially exceedingthe melting-point of cyanid, thereby forming dialkalicyanamid, thenraising the temperature of the mass to about 750o to 800o centigrade,thereby causing the dialkalicyanamid to combine with the carbon, formingalkali cyanid, substantially as and for the purposes set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHANNES PFLEGER.

Witnesses:

JEAN GRUND, FRANZ HAssLACHER.

